1. Field
This disclosure is directed to a crosslinkable thermoset monomer, a composition for producing a printed circuit board comprising the crosslinkable thermoset monomer, and a printed circuit board using the composition. More specifically, the crosslinkable thermoset monomer has acetylene groups as crosslinking groups introduced at both ends of the backbone.
2. Description of the Related Art
Recent advances in information and communication technologies have transformed our society into a high-tech communication and information society. The trend toward miniaturization and high performance of electronic devices, for example, mobile phones and personal computers, has led to high-density integration of printed circuit boards as essential elements of the electronic devices. Such high-density integration has mainly been achieved by layering printed circuit boards, reducing the thickness of printed circuit boards, making the diameter of through-holes smaller and reducing the interval of holes. Under these circumstances, there is a need for novel board materials with higher performance.
The use of high operating frequencies for rapid processing of much information in electronic information devices such as computers involves the problems of transmission loss and signal delay. Generally, a signal delay in a printed circuit board increases linearly with the square root of the relative permittivity of an insulating material around interconnection lines. Thus, low-permittivity board materials are needed to produce boards requiring a high transmission rate.
Liquid crystal polyester resins are board materials that have a dielectric constant as low as 3.0 and exhibit excellent characteristics, such as high heat resistance and low moisture absorption. The production of boards using liquid crystal polyester resins is dependent on melting processes, such as injection molding, because most of the liquid crystal polymers are insoluble or slightly soluble in solvents. However, a printed circuit board produced by injection or extrusion using a liquid crystal polymer is highly anisotropic due to the orientation of the polymer chains, causing difficulty in designing a circuit and poor mechanical properties.
Bismaleimide-triazine (“BT”) and glass epoxy resins (e.g., (“FR-4”) are currently used as typical board materials. However, these materials are not successful in providing satisfactory results, such as excellent mechanical properties, low permittivity, high heat resistance, low thermal expansion and low moisture absorption, for future packaging technologies. Thus, there is a need to develop novel materials that can meet the requirements for next-generation boards.